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Subject[PATCH 37/91] alpha: fix several security issues
2.6.27-longterm review patch.  If anyone has any objections, please let us know.

------------------

commit 21c5977a836e399fc710ff2c5367845ed5c2527f upstream.

Fix several security issues in Alpha-specific syscalls. Untested, but
mostly trivial.

1. Signedness issue in osf_getdomainname allows copying out-of-bounds
kernel memory to userland.

2. Signedness issue in osf_sysinfo allows copying large amounts of
kernel memory to userland.

3. Typo (?) in osf_getsysinfo bounds minimum instead of maximum copy
size, allowing copying large amounts of kernel memory to userland.

4. Usage of user pointer in osf_wait4 while under KERNEL_DS allows
privilege escalation via writing return value of sys_wait4 to kernel
memory.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/alpha/kernel/osf_sys.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)

Index: longterm-2.6.27/arch/alpha/kernel/osf_sys.c
===================================================================
--- longterm-2.6.27.orig/arch/alpha/kernel/osf_sys.c 2012-02-05 22:34:33.893915202 +0100
+++ longterm-2.6.27/arch/alpha/kernel/osf_sys.c 2012-02-05 22:34:40.104915063 +0100
@@ -451,7 +451,7 @@
return -EFAULT;

len = namelen;
- if (namelen > 32)
+ if (len > 32)
len = 32;

down_read(&uts_sem);
@@ -639,7 +639,7 @@
down_read(&uts_sem);
res = sysinfo_table[offset];
len = strlen(res)+1;
- if (len > count)
+ if ((unsigned long)len > (unsigned long)count)
len = count;
if (copy_to_user(buf, res, len))
err = -EFAULT;
@@ -695,7 +695,7 @@
return 1;

case GSI_GET_HWRPB:
- if (nbytes < sizeof(*hwrpb))
+ if (nbytes > sizeof(*hwrpb))
return -EINVAL;
if (copy_to_user(buffer, hwrpb, nbytes) != 0)
return -EFAULT;
@@ -1061,6 +1061,7 @@
{
struct rusage r;
long ret, err;
+ unsigned int status = 0;
mm_segment_t old_fs;

if (!ur)
@@ -1069,13 +1070,15 @@
old_fs = get_fs();

set_fs (KERNEL_DS);
- ret = sys_wait4(pid, ustatus, options, (struct rusage __user *) &r);
+ ret = sys_wait4(pid, (unsigned int __user *) &status, options,
+ (struct rusage __user *) &r);
set_fs (old_fs);

if (!access_ok(VERIFY_WRITE, ur, sizeof(*ur)))
return -EFAULT;

err = 0;
+ err |= put_user(status, ustatus);
err |= __put_user(r.ru_utime.tv_sec, &ur->ru_utime.tv_sec);
err |= __put_user(r.ru_utime.tv_usec, &ur->ru_utime.tv_usec);
err |= __put_user(r.ru_stime.tv_sec, &ur->ru_stime.tv_sec);



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